Arms not spinning

Over the last few days I’ve noticed that my dishes aren’t getting clean at all; I’ve opened up the washer during the washing cycle and noticed that while water is coming out of the spinning arms, the arms are not moving.

Since the top arm is not mechanized, I can only assume that i’ts not moving because not enough water is getting to it.

The lower arm, seen here:

http://www.appliancepartspros.com/part_details.aspx?part_id=2920589&image=1

here, also is not moving. I think it’s mechanized. It does spin freely when I spin it by hand. My question is, just how do I remove this thing? I’m not seeing any obvious screws that I can get to.

I’m not very handy so I have NOT pulled out the washer from under the countertop. I’m also stingy so if it’s gonna cost me $200 for someone to come out and repair it, I’d rather just junk it and get a new one for $350. However, I’m willing to take a shot at fixing it on my own.

Any thoughts on my problem? Any help would be great!